Fold-out shelving unit made of cardboard or a similar material

ABSTRACT

The fold-out shelving unit comprises a rear panel ( 1 ), side panels ( 2 ) movable between a folded position, wherein said panels are coplanar, and an expanded position, wherein the side panels ( 2 ) are perpendicular to the rear panel ( 1 ), a moving support panel ( 3 ) extending from one to the other of the side panels ( 2 ) and a shelf panel ( 4 ) foldable over the rear panel ( 1 ). The support panel ( 3 ) and the shelf panel ( 4 ) are cinematically linked to one another and to the side panels ( 2 ) by first and second cinematic linking means so that the support panel ( 3 ) gets closer and away parallel to the rear panel ( 1 ) and the shelf panel ( 4 ) pivots relative to the rear panel ( 1 ) when the side panels ( 2 ) move between the folded position and the expanded position.

FIELD OF THE ART

The present invention relates to fold-out shelving unit made of cardboard or a similar material, such as corrugated cardboard, corrugated plastic, lightweight cardboard, etc. The fold-out shelving unit of the present invention is useful, for instance, as a sales stand to display goods at a sales point and, therefore, it comprises one or more shelves capable of holding up goods, including relatively heavy articles, such as books, preserve tins or jars, bottles, etc.

BACKGROUND OF THE INVENTION

International patent application WO-A-2009037368 describes a self-expanding, foldable structure for a shelved sales stand, made of cardboard or a similar material, that comprises a main piece defining a rear panel and side panels hingedly attached to side edges opposite said rear panel, wherein the side panels can be moved between a folded position, wherein said side panels and the rear panel are substantially parallel or coplanar, and an expanded position, wherein the side panels are substantially perpendicular to the rear panel. The shelving unit includes shelf panels, each having a rear edge hingedly attached to the rear panel so that it can be moved between a folded position, wherein the shelf panel is substantially parallel to the rear panel and the side panels when the latter are in the folded position, and an expanded position, wherein the shelf panel forms trihedral angles with the rear panel and the side panels when the latter are in the expanded position. The shelf panels are connected to the side panels by means of linking panels establishing a cinematic linkage between the side walls and the shelf panels and supporting the shelf panels on their side edges in the expanded position. A number of elastic members are arranged to push the side walls towards the expanded position.

Said cinematic linkage causes a movement of any of the panels to be automatically communicated to the remaining panels. Thus, when the elastic members move the side panels from the folded position towards the expanded position, the shelf panels are also automatically moved towards the expanded position, and, when the side panels are manually moved from the expanded position towards the folded position against the force of the elastic members, the shelf panels are also automatically moved towards the folded position.

One drawback of the linking panels described in said international patent application WO-A-2009037368 is that, in the expanded position, they only support the shelf panels by their side edges, and this entails the risk of the shelf panels sagging or failing under the weight of the articles arranged on top, unless the shelf panels are made of the substantially stiff material or their front edges are reinforced with fins or folds that add complexity to the structure.

U.S. Pat. No. 6,715,623 discloses a fold-out shelving unit made of corrugated cardboard comprising a main piece defining a rear panel and side panels hingedly attached to side edges opposite said rear panel. The side panels can be moved between a folded position, wherein said side panels and the rear panel are substantially parallel or coplanar, and an expanded position, wherein the side panels are substantially perpendicular to the rear panel. Support panels extend from one to the other of the side panels that are obtained by a number of cuts in said main piece and adopt a substantially parallel position and separate from the rear panel when the shelving unit is in said expanded position. The shelving unit includes shelf panels, each having a rear edge hingedly attached to the rear panel so that it can be moved between a folded position, wherein the shelf panel is substantially parallel to the rear panel and the side panels when the latter are in the folded position, and an expanded position, wherein the shelf panel forms trihedral angles with the rear panel and the side panels when the latter are in the expanded position. When the shelf panels are in the expanded position, their front regions are supported along their entire width by the support panels.

One drawback of said U.S. Pat. No. 6,715,623 is that it does not comprise a cinematic linkage between the panels embedded in the main piece and the shelf panels, so that, in order to move the shelving unit from the expanded position to the folded position, it is necessary, firstly, to individually fold the shelf panels and keep them in the folded position before the side and support panels can be folded. In addition, this makes it impossible or fairly complex to incorporate elastic members arranged to push the shelving unit towards the expanded position so that the fold-out shelving unit is self-expanding.

DISCLOSURE OF THE INVENTION

The present invention contributes to alleviate the above and other drawbacks by providing fold-out shelving unit made of cardboard or a similar material, comprising a rear panel and side panels hingedly attached to opposite side edges of said rear panel so that they can be moved between a folded position, wherein said side panels and the rear panel are substantially parallel or coplanar, and an expanded position, wherein the side panels are substantially perpendicular to the rear panel. In addition, the shelving unit comprises at least one support panel extending from one to the other of the side panels in a position substantially parallel to the rear panel (1), and separate therefrom, in said expanded position, and at least one shelf panel movably attached to the rear panel and/or to the side panels so that it can be moved between a folded position, wherein said shelf panel is substantially parallel to the rear panel and to the side panels when the latter are in the folded position, and an expanded position, wherein the shelf panel forms trihedral angles with the rear panel and with the side panels when the latter are in the expanded position, and is directly or indirectly supported by said support panel. Retention means are arranged to keep the rear, side and support panels in the expanded position.

The support panel is cinematically linked to the side panels by first cinematic linking means so that the support panel gets closer and away parallel to the rear panel when the side panels move between the folded position and the expanded position, and the shelf panel is cinematically linked to the support panel by second cinematic linking means so that the shelf panel pivots relative to the rear panel when the support panel moves between the folded position and the expanded position.

Said second cinematic linking means comprise at least one cinematic linking panel having a first edge hingedly attached to the support panel and an opposite second edge hingedly attached to the shelf panel in a position between the support panel and the rear panel when they are in the expanded position. In one embodiment, the shelf panel and the cinematic linking panel are formed as one single cardboard piece having a transverse hinge, so that, in the expanded position, the shelf panel and the cinematic linking panel are arranged coplanarily in a horizontal position, jointly offering a complete shelf. Said transverse hinge is preferably provided by a V-cut which does not affect the underside of the single cardboard piece.

In an embodiment, the first cinematic linking means comprise connection panels having a first edge hingedly attached to each side end of the support panel and a second edge hingedly attached to each side panel in a position between the support panel and the rear panel when they are in the expanded position. In another alternative embodiment, each side panel comprises a longitudinal folding line substantially parallel to the corresponding side edge of the rear panel and located between the support panel and the rear panel when they are in the expanded position, and the side edges of the support panel are hingedly attached to the side panels on or near their free front edges.

One of the shelves located on the bottom region of the shelving unit can form a pedestal, in which case the corresponding support panel preferably extends from the shelf panel to the floor or support surface on which the shelving unit rests in the expanded position. Between the shelf panel and the floor or support surface, there is a foldable support structure arranged that comprises two or more vertical structure panels hingedly attached to one another. One of said structure panels is hingedly attached to one of the rear, side and support panels, and another of the structure panels is hingedly attached to another of the rear, side and support panels, so that the foldable support structure is moved between a folded position and an expanded position along with the rear, side and support panels when the latter are moved between the folded position and the expanded position.

The structure panels have top edges and bottom edges and their height is selected so that said top edges are arranged to support the shelf panel, whereas said bottom edges are arranged to rest on the floor or support surface. Thus, thanks to the vertical structure panels, the shelf panel is capable of holding up heavy articles even though the fold-out shelving unit is entirely made of corrugated cardboard or a similar material.

Optionally, one or more elastic members, such as annular rubber bands, are arranged to push the rear, side and support panels towards the expanded position and keep them therein. Thus, thanks to the elastic member or members, the fold-out shelving unit is self-expanding, since it is automatically expanded from the folded position to the expanded position, whereas the folding from the expanded position to the folded position is carried out manually against the force of the elastic members. Alternatively, since the panels are cinematically linked, the expansion and the folding can be carried out manually with ease, and alternative retention means, elastic or otherwise, can be used to keep them in the expanded position.

Preferably, the rear panel and the side panels comprise at least one transversal folding line substantially perpendicular to the side edges of the rear panel so that the shelving unit can be moved from the folded position to a compact folded position by bending the rear panel and the side panels along said transversal folding line. If the folded shelving unit is self-expanding through the incorporation of elastic members, said compact folded position is stable, since the fold along the transversal folding line keeps the elastic means from moving the shelving unit from the compact folded position to the expanded position. The unfolding from the compact folded position must be manually initiated until the point is reached from which the elastic means actuate and the expansion to the expanded position is automatically carried out in a few seconds.

In order to get the transversal folding line to form a spine of a desired width, this comprises two mutually parallel first complementary folding lines separated by a first distance. If the material is corrugated cardboard or a similar material, each first complementary folding line comprises, in at least one section of its length, a partial cut-off line on an outer side of the panel and a folding line on the opposite, inner side of the panel. In some places, one or more of the rear and side panels have a multilayered region, wherein the transversal folding line comprises two mutually parallel second complementary folding lines separated by a second distance smaller than said first distance. Each second complementary folding line comprises a partial cut-off line on an outer side of the multilayered region of the panel and a folding line on the opposite, inner side. The first and second complementary folding lines are bounded by a complete transversal cut-off line. Said second distance is approximately equal to the first distance minus two times the thickness of the additional layer or layers of said multilayered region.

In an embodiment, on the shelf panel there is a stepped structure comprising one or more stepped shelf panels and one or more stepped support panels hingedly attached to each other. All the stepped support panels have a bottom edge hingedly attached to the shelf panel, whereas the top stepped shelf panel has a rear edge hingedly attached to the rear panel. Obviously, the stepped structure might comprise one single step with one stepped shelf panel and one stepped support panel.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other characteristics and advantages will be more fully understood from the following detailed description of exemplary embodiments with reference to the attached drawings, wherein:

FIG. 1 is a perspective view of a fold-out shelving unit made of cardboard or a similar material according to an embodiment of the present invention in an intermediate position between a folded position and an expanded position;

FIG. 2 is an exploded perspective view showing some members forming a shelf of the fold-out shelving unit of FIG. 1;

FIG. 3 is a side view of the members of FIG. 2 assembled in an expanded position;

FIG. 4 is a side view of the members of FIG. 2 assembled in an intermediate position between the folded position and the expanded position;

FIG. 5 is a perspective view of the fold-out shelving unit of FIG. 1 in the expanded position;

FIG. 6 is a perspective view of a variant of the fold-out shelving unit of FIG. 5 with one single shelf forming a base in the expanded position;

FIG. 7 is a side view of a variant of the members forming the shelf of FIG. 2 assembled in an expanded position;

FIG. 8 is a side view of the members forming the shelf of FIG. 7 in an intermediate position between the folded position and the expanded position;

FIG. 9 is a side view of another variant of the members forming the shelf of FIG. 2 assembled in an expanded position;

FIG. 10 is a side view of the members forming the shelf of FIG. 9 in an intermediate position between the folded position and the expanded position;

FIG. 11 is a partial view of the fold-out shelving unit in the intermediate position showing a variant of the members forming the shelf of FIGS. 9 and 10;

FIG. 12 is a side view of the members forming the shelf of FIG. 11 in an expanded position;

FIG. 13 is a perspective view of a fold-out shelving unit made of cardboard or a similar material according to another embodiment of the present invention in an intermediate position between a folded position and an expanded position;

FIG. 14 is a perspective view of the fold-out shelving unit of FIG. 13 in the expanded position;

FIG. 15 is a perspective view of a fold-out shelving unit made of cardboard or a similar material according to yet another embodiment of the present invention in an expanded position;

FIG. 16 is a side view of some members forming a shelf of the fold-out shelving unit of FIG. 15 in an expanded position;

FIG. 17 is a side view of the members of FIG. 16 in an intermediate position between the folded position and the expanded position;

FIG. 18 is a perspective view of a fold-out shelving unit made of cardboard or a similar material according to a variant of the shelving unit of FIG. 13 in an intermediate position between a folded position and an expanded position, wherein a cinematic linking panel has been omitted to better show a foldable support structure according to an embodiment;

FIG. 19 is an exploded perspective view showing some members forming the foldable support structure of FIG. 18;

FIG. 20 is an exploded perspective view of the members forming the foldable support structure of FIG. 18 in the expanded position;

FIG. 21 is a perspective view of a fold-out shelving unit made of cardboard or a similar material according to a variant of the shelving unit of FIG. 13 in an intermediate position between a folded position and an expanded position, wherein a cinematic linking panel has been omitted to better show a foldable support structure according to another embodiment;

FIG. 22 is a plan view of the unfolding of a member forming the structure of the foldable support of FIG. 21;

FIG. 23 is a perspective view of the member forming the structure of the foldable support of FIG. 18 in the expanded position;

FIG. 24 is a perspective view of a fold-out shelving unit made of cardboard or a similar material according to yet another embodiment of the present invention in an intermediate position between a folded position and an expanded position;

FIG. 25 is a plan view of the unfolding of the shelving unit of FIG. 24 in the intermediate position;

FIG. 26 is a perspective view of a fold-out shelving unit made of cardboard or a similar material according to the present invention in an intermediate position between the folded position and a compact folded position by folding along a transversal folding line;

FIG. 27 is a perspective view of the shelving unit of FIG. 26 in the compact folded position;

FIG. 28 is a perspective view of an enlarged detail showing the inner side of the transversal folding line in a multilayered region of a shelving side panel in an intermediate position between the folded position and a compact folded position;

FIG. 29 is a perspective view of an enlarged detail showing the outer side of the transversal folding line in a multilayered region of a shelving side panel in an intermediate position between the folded position and a compact folded position;

FIG. 30 is a perspective view of a fold-out shelving unit made of cardboard or a similar material according to one further embodiment of the present invention including a stepped structure in an intermediate position between a folded position and an expanded position;

FIG. 31 is a perspective view of the fold-out shelving unit of FIG. 30 in the expanded position;

FIG. 32 is a side view of some members forming the stepped structure of FIGS. 30 and 31 in an intermediate position between a folded position and an expanded position;

FIG. 33 is a perspective view of a fold-out shelving unit made of cardboard or a similar material according to another embodiment of the present invention in an intermediate position between a folded position and an expanded position;

FIG. 34 is a perspective view of the fold-out shelving unit of FIG. 33 in the expanded position;

FIG. 35 is an enlarged view of detail XXXV of FIG. 34;

FIG. 36 is an exploded perspective view showing some members forming a shelf according to a variant of the fold-out shelving unit of FIG. 1;

FIG. 37 is a perspective view of a fold-out shelving unit made of cardboard or a similar material according to yet another embodiment of the present invention in an intermediate position between a folded position and an expanded position;

FIG. 38 is an enlarged view of detail XXXVIII of FIG. 37;

FIG. 39 is a perspective view of the fold-out shelving unit of FIG. 37 in the expanded position;

FIG. 40 is a side view of some members forming the shelf of the fold-out shelving unit of FIG. 37 assembled in an expanded position;

FIG. 41 is a side view of the members of FIG. 40 assembled in an intermediate position between the folded position and the expanded position;

FIG. 42 is a perspective view of a fold-out shelving unit made of cardboard or a similar material according to one further embodiment of the present invention including a stepped structure in an intermediate position between a folded position and an expanded position;

FIG. 43 is a perspective view of the fold-out shelving unit of FIG. 42 in a position close to the folded position;

FIG. 44 is a perspective view of the fold-out shelving unit of FIG. 42 in the folded position;

FIG. 45 is a perspective view of a fold-out shelving unit made of cardboard or a similar material according to an additional embodiment of the present invention, in a partially expanded situation and with some of its components detached; and

FIG. 46 is a perspective view of an enlarged detail of the fold-out shelving unit of FIG. 45 with some components depicted in dashed lines for clarity.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

With reference, firstly, to FIGS. 1 to 5, the fold-out shelving unit made of cardboard or a similar material according to one embodiment of the present invention comprises a rear panel 1 having opposite side edges and side panels 2 hingedly attached to said opposite side edges of the rear panel 1 so that they can be moved between a folded position (not shown), wherein said side panels 2 and the rear panel 1 are substantially parallel or coplanar, and an expanded position (shown in FIG. 5), wherein the side panels 2 are substantially perpendicular to the rear panel 1.

Although it is not imperative, the rear and side panels 1, 2 are preferably made of one single piece, the hinged attachment therebetween comprising folding lines including split lines, partial cut-off lines or combinations of both. In addition, the rear and side panels 1, 2 preferably comprise a transversal folding line 15 substantially perpendicular to the side edges of the rear panel 1 that allows folding the rear panel 1 and the side panels 2 from the folded position to a compact folded position, as will be described in further detail below.

In addition, the shelving unit of FIGS. 1 to 5 comprises a couple of shelf panels 4, each of which has a rear edge hingedly attached to the rear panel 1 so that it can be moved between a folded position, wherein said shelf panel 4 is substantially parallel to the rear panel 1 and to the side panels 2 when the latter are in the folded position, and an expanded position, wherein the shelf panel 4 forms trihedral angles with the rear and side panels 1, 2 (FIG. 5). Alternatively or additionally, the shelving panels might be linked to the side panels through linking panels, such as those described in the aforementioned international patent application WO-A-2009037368 allowing the same movements.

Each shelf panel 4 is associated to a support panel 3 that, in the expanded position, extends from one to the other of the side panels 2 in a position substantially parallel to the rear panel 1, and separate therefrom. This support panel 3 is cinematically linked to the side panels 2 by first cinematic linking means so that the support panel 3 gets closer and away parallel to the rear panel 1 when the side panels 2 move between the folded position and the expanded position. In the embodiment of FIGS. 1 to 5, said first cinematic linking means comprise a couple of connection panels 6, each of which has a first edge, or front edge, hingedly attached to a corresponding side end of the support panel 3 and a second edge, or rear edge, hingedly attached to a corresponding side panel 2 in a position located between the support panel 3 and the rear panel 1 when they are in the expanded position.

In order to facilitate the movements of the fold-out shelving unit between the folded and expanded positions, the distance between the front and rear edges of the connection panel 6 is equal to the distance between the front edge of the connection panel 6 and the rear edge of the corresponding side panel 2 attached to the side edge of the rear panel 1. In general, the side panels 2 open outwardly to transition from the expanded position to the folded position.

In addition, the shelf panel 4 is cinematically linked to the support panel 3 by second cinematic linking means so that the shelf panel 4 pivots relative to the rear panel 1 when the support panel 3 moves between the folded position and the expanded position. In the embodiment of FIGS. 1 to 5, these second cinematic linking means comprise a cinematic linking panel 5 having a first edge hingedly attached to the support panel 3 and a second opposite edge hingedly attached to the shelf panel 4 in a position between the support panel 3 and the rear panel 1 when they are in the expanded position.

With this construction, all the panels of the fold-out shelving unit are cinematically linked to each other, so that the movement of any of them causes the movement of the others. By optionally arranging one or more elastic members 14, such as, for instance, annular rubber bands, so that they will push the rear, side, support and shelf panels 1, 2, 3, 4 towards the expanded position, the foldable sales stand further becomes self-expanding, that is, capable of expanding automatically from the folded position to the expanded position.

In the embodiment of FIGS. 1 to 5, the elastic members 14 in the shape of annular rubber bands are arranged to pull the side panels 2 towards one another, although they might be alternatively arranged to pull other panels towards one another by virtue of the cinematic linkage among all of them. For practical and aesthetic reasons, the elastic members are arranged adjacent to an underside of the shelf panels 4 so that they are hidden when the fold-out shelving unit is in the expanded position.

Obviously, the force exerted by the elastic members 14 is used, in addition, to keep the panels of the fold-out shelving unit in the expanded position. In order to prevent the relaxation effect that the annular rubber bands can experience when they are kept under tension for a long period of time, it may be convenient to install two or more annular rubber bands associated to each shelf panel, each individual annular rubber band being subject to a smaller tension than if there was only one. Alternatively, if the fold-out shelving unit is not self-expanding, other retention means, elastic or otherwise, are foreseen in order to keep the rear, side, support and shelf panels 1, 2, 3, 4 in the expanded position, such as, for instance, one or more surrounding bands or a skirting board in which the bottom regions of the rear and side panels 1, 2 are inserted.

In FIGS. 2 to 4 there is shown the construction and the operation of one of the shelves of the foldable structure according to an embodiment. The support panel 3 is made of one single piece of corrugated cardboard or a similar material that has a couple of folding lines defining fastening fins 3 a adjacent to their side edges for the hinged attachment of the support panel 3 to the connection panels 6. Each of the connection panels 6 is, in turn, made of one corresponding piece of corrugated cardboard or a similar material having one folding line defining one fastening fin 6 a adjacent to its rear edge for the hinged attachment of the connection panels 6 to the respective side panels 2. Although it is not imperative, the length of the fastening fins 6 a is preferably the same as the length of the connection panels 6 so as to aid the positioning thereof relative to the side panels 2. In each of said fastening fins 6 a there is a die-cut hooking member 6 b wherein the flexible member 14 is hooked.

The shelf panel 4 is likewise made of one piece of corrugated cardboard or a similar material having a folding line defining a fastening fin 4 a adjacent to its rear edge for the hinged attachment of the shelf panel 4 to the rear panel 1. Lastly, the cinematic linking panel 5 is made of one corresponding piece of corrugated cardboard or a similar material having a couple of folding lines defining fastening fins 5 a, 5 b adjacent to its front and rear edges for the hinged attachment of the cinematic linking panel 5 to the support panel 3 and to the shelf panel 4, respectively. For instance, the attachment of the various fastening fins to the respective panels is carried out by bonding.

As shown in FIG. 3 (valid both for the top shelf and the lower shelf), the shelf panel 4 has a length selected so that, in the expanded position, a front region thereof is directly supported by the top edge of the support panel 3, while the cinematic linking panel 5 remains in a sloping position between the shelf panel 4 and the support panel 3, which contributes to supporting an intermediate region of the shelf panel 4. Preferably, the cinematic linking panel 5 forms an acute angle with the shelf panel 4 in the expanded position. For instance, when the support panel 3 is moved towards the rear panel 1 (FIG. 4), whether it be by direct pressure thereon or as a result of the movement of the side panels 2 towards the folded position, the cinematic folding panel 5 pushes the shelf panel 4 upwards, towards the folded position.

In the embodiment shown in FIGS. 1 to 5, the support panel 3 associated to the top shelf has low height, whereas the support panel 3 associated to the lower shelf extends from the corresponding shelf panel 5 down to the floor or another support surface on which the fold-out shelving unit is located, forming a base. The fastening fins 6 a have considerable height and the connection panels 6 have increasing height from the support panel 3 up to the corresponding fastening fins 6 a. Both the connection panels 6 and the fastening fins 6 a protrude above the corresponding shelf panels 4 in the expanded position. In the top shelf, the relatively large height of the connection panels 6 and the corresponding fastening fins 6 a provides great sturdiness to the support panel 3 notwithstanding its scant height and its being supported on the air.

FIG. 6 shows a variant of the embodiment shown in FIGS. 1 to 5 wherein the top shelf has been omitted and there is only one lower shelf panel 4 associated to the support panel 3 forming a base.

FIGS. 7 and 8 show one variant of the members 3, 4, 5, 6, 6 a forming the top shelf, which are thoroughly analogous to the ones previously described in connection with FIGS. 3 and 4, except that, in this case, the connection panels 6 and their corresponding fastening fins 6 a, despite their having considerable height, extend downwards from the level of the shelf panel 4, so that they do not protrude above the corresponding shelf panels 4 in the expanded position. The relatively large height of the connection panels 6 and the corresponding fastening fins 6 a provides sturdiness to the support panel 3.

FIGS. 9 and 10 show another variant of the members 3, 4, 5, 6, 6 a forming the top shelf, which are analogous to the ones previously described in connection with FIGS. 3 and 4, except that, in this case, the connection panels 6 and their corresponding fastening fins 6 a have substantially the same height as the support panel 3. In this variant, the support panel 3 has less sturdiness and it is adequate to hold up light articles.

FIGS. 11 and 12 show yet another variant of the members 3, 4, 5, 6, 6 a forming the top shelf, which are analogous to the ones previously described in connection with FIGS. 9 and 10 with the addition of a notch 6 c made on the bottom edge of each connection panel 6 near the support panel 3 so it will engage a projection 9 affixed on the inner side of the corresponding side panel 2 when the shelving unit is in the expanded position. This way, the projections 9 support the connection panels 6 in the expanded position and confer sturdiness to the support panel 3 and the shelf panel 4. The projections can be made, for instance, from pieces of corrugated cardboard or a similar material fastened to the side panels. Optionally, the notches 6 c can be omitted, in which case it will be a bottom edge of each connection panel 6 the one being supported on the corresponding projection 9 in the expanded position.

FIGS. 13 and 14 show a fold-out shelving unit according to a variant of the fold-out shelving unit shown in FIG. 6, which only has one lower shelf panel 4 associated to a support panel 3 forming a base. The difference in this variant is that the connection panels 6 have much greater length than in the shelving unit of FIG. 6, and they are connected near the free front edges of the corresponding side panels 2. As a result, the support panel 3 is located forwardly of the free front edges of the side panels 2 and the shelf panel 4 leans on the top edge of the support panel 3 in the expanded position.

The result is a fold-out shelving unit with a base provided with a shelf panel 4 of noticeable larger dimensions that the one of the fold-out shelving unit shown in FIG. 6. In the expanded position, the support panel 3, the shelf panel 4 and the connection panels 6 protrude noticeably from the side panels 2, whereas in the folded position the fold-out shelving unit would occupy exactly the same space as the fold-out shelving unit shown in FIG. 6, since the maximum width of the shelving unit in the folded position is defined by the free front edges of the side panels 2 rather than by the members forming the shelf and the base.

FIG. 15 shows a variant of the fold-out shelving unit shown in FIGS. 13 and 14, wherein the only difference resides in that the rear edge of the shelf panel 4 is hingedly attached to the rear panel 1 at a lower level than the top edges of the support and connection panels 3, 6, and the shelf panel 4 has its length selected so that a front region thereof will be supported in the expanded position by a projection 8 protruding from the inner side of the support panel 3 at a lower level than its top edge. The result is that the base forms a container, wherein top portions of the support and connection panels 3, 6 provide railings surrounding the front portion of the shelf panel 4, whose rear portion is defined by the rear and side panels 1, 2. The projection 8 can be formed, for instance, by the top edge of a board of corrugated cardboard or a similar material affixed to the inner side of the support panel 3.

FIGS. 16 and 17 show the operation of the container formed by the base of the fold-out shelving unit according to one variant of FIG. 15. In them there can be observed the arrangement of a cinematic linking panel 5 with a front edge hingedly attached to the support panel 3 or to the board providing the projection 8, and a rear edge hingedly attached to the shelf panel 4 and an intermediate region thereon. In the expanded position (FIG. 16), the front region of the shelf panel 4 rests on the projection 8 and the cinematic linking panel 5 remains in a sloping position between the shelf panel 4 and the support panel 3, so that it contributes to supporting an intermediate region of the shelf panel 4.

FIG. 18 shows another variant of the fold-out shelving unit shown in FIGS. 13 and 14 that additionally includes a foldable support structure 10 arranged between the shelf panel 4 and the floor or another support surface on which the shelving unit rests in the expanded position. In FIG. 18 the cinematic linking panel 5 has been omitted to show the support structure 10 more clearly, although the fold-out shelving unit of FIG. 18 actually comprises a couple of narrow cinematic linking panels 5 (not shown) installed in a manner analogous to that described above on both sides of the support structure 10 so as not to interfere therewith.

FIGS. 19 and 20 show said support structure 10 according to the embodiment of FIG. 18, which comprises two vertical structure panels 11, 12 of corrugated cardboard or a similar material, each of which has a one vertical folding line 11 a, 12 a in its middle region and a couple of linear cuts 11 b, 12 b parallel to said vertical folding line 11 a, 12 a on opposite sides of said vertical folding line 11 a, 12 a. The structure panels 11, 12 also have respective fastening fins 11 c, 12 c on opposite edges thereof. The two structure panels 11, 12 folded by their vertical folding lines 11 a, 12 a are assembled by the mutual engagement of their linear cuts 11 b, 12 b, as shown in FIG. 20.

In an operational situation (FIG. 18), the support structure 10 is housed inside the fold-out shelving unit base with the fastening fin 11 c of one of the structure panels 11 attached to the rear panel 1 and the fastening fin 12 c of the other structure panel 12 attached to the inner side of the support panel 3. This way, the support structure 10 is moved between a folded position and an expanded position along with the rear, side and support panels 1, 2, 3 when the latter are moved between the folded position and the expanded position. The height of the support panels 11, 12 is selected so that, in the expanded position, top edges thereof are arranged to support the shelf panel 4 and bottom edges thereof are arranged to rest on the floor or another support surface. The structure panels 11, 12 preferably include respective windows 11 d, 12 d (FIG. 19) which the elastic member 14 goes through in the operational situation (FIG. 18).

FIG. 21 shows a fold-out shelving unit similar to the one shown in FIG. 18, but including a variant of the foldable support structure 10 housed inside the base. In this variant, the foldable structure comprises a plurality of vertical structure panels 13 a-13 e hingedly attached to each other by means of vertical hinge lines forming an accordion structure. In the operational situation, one of the structure panels 13 a located at one end of the accordion structure is hingedly attached to the rear panel 1 and the structure panel 13 e located at the other, opposite end of the accordion structure is hingedly attached to the support panel 3. The support structure 10 moves between folded and expanded positions along with the remaining shelving panels. In the expanded position, the shelf panel 4 is supported on one of the top edges of the structure panels 13 a-13 e, whereas bottom edges thereof rest on the floor or another support surface.

As shown in FIGS. 22 and 23, the structure panels 13 a-13 e are preferably obtained from one single board of corrugated cardboard or a similar material provided with parallel folding lines 21 that provide the hinged attachment therebetween, and from the structure panels 13 a, 13 e located at opposite ends of the board there extend fastening fins 22 a, 22 b providing hinged attachment to the rear and support panels 1, 3. Some of the selected structure panels 13 b, 13 d preferably include respective windows 23 (FIGS. 22 and 23) which respective elastic members 14 go through in the operational situation (FIG. 18).

FIGS. 24 and 25 show another alternative embodiment of the fold-out shelving unit of the present invention, wherein, instead of the connection panels 6 previously described, the first cinematic linking means comprise, on each side panel 2, a longitudinal folding line 7 substantially parallel to the corresponding side edge of the rear panel 1. This longitudinal folding line 7 is located between the support panel 3 and the rear panel 1 when the shelving unit is in the expanded position. In this embodiment, the support panel 3 has its opposite side edges hingedly attached to the side panels 2, near their free front edges or directly on its free front edges, and the cinematic linking panel 5 is hingedly attached to the rear and support panels 1, 3, as previously described.

For instance, from the opposite side edges of the support panel 3 there extend fastening fins 3 a for the hinged attachment to side panels, and in the free ends of said fastening fins 3 a hooking members 3 b (FIG. 25) are formed on which the flexible member 14 hooks. In this embodiment, when the fold-out shelving unit moves from the expanded position to the folded position, the rear half of the side panels opens outwardly while the front half folds inwardly and overlaps the rear half. For this reason, in the folded situation the shelving unit has a smaller width than that of the previously described embodiments.

FIGS. 26 and 27 illustrate how a fold-out shelving unit according to the present invention can be moved from the folded position (close to the one shown in FIG. 26) to a compact folded position (FIG. 27). To that end, the rear panel 1 and the side panels 2 comprise a transversal folding line 15 substantially perpendicular to the side edges of the rear panel 1, so that the shelving unit can be moved from the folded position to the compact folded position by bending the rear panel 1 and the side panels 2 along said transversal folding line 15. The members 3, 4, 5, 6 forming the top shelf are arranged above the transversal folding line 15 and the members 3, 4, 5, 6 forming the lower shelf and the base are found below the transversal folding line 15, so that they do not interfere with the folding.

In the embodiment shown in FIGS. 26 and 27, the top portion of the rear and side panels 1, 2 is folded forwardly, so that the members 3, 4, 5, 6 forming the top shelf and the lower shelf with the base are left overlapping each other and substantially covered by the corresponding halves of the rear and side panels 1, 2 when the shelving unit is in the compact folded position (FIG. 27). In other embodiments (not shown), however, the top portion of the rear and side panels 1, 2 can be folded backwards, that is, with the two halves of the rear and side panels 1, 2 arranged back to back on the inner side and the members 3, 4, 5, 6 forming the top shelf and the lower shelf with the base arranged on the outer sides.

FIGS. 28 and 29 show a detail of the inner side and the outer side, respectively, of the transversal folding line 15 in a region where the side panel 2 has a fold that provides a two-layered region 2 a. For instance, this fold and the two-layered region 2 a are located along the free front edges of the side panels 2 to reinforce said edges and, at the same time, to present a smooth edge 2 b hiding the internal structure of the corrugated cardboard or a similar material, which would be visible in said edges if the fold did not exist.

In order to facilitate the folding of the two-layered region 2 a without the occurrence of crushing and tearing, the transversal folding line 15 comprises, in the single-layered regions 2, two mutually parallel first complementary folding lines 15 a, 15 b separated by a first distance d1, and, in the two-layered regions 2 a, two mutually parallel first complementary folding lines 15 c, 15 d separated by a second distance d2 smaller than said first distance d1. Each of said first complementary folding lines 15 a, 15 b comprises, in at least one section of its length, a partial cut-off line on an outer side of the panel (FIG. 29) and a folding line on the opposite, inner side of the panel (FIG. 28), and each of the second complementary folding lines 15 c, 15 d comprises a partial cut-off line on an outer side of the two-layered region 2 a of the panel (FIG. 29) and a folding line on the opposite, inner side of the two-layered region (2 a) of the panel (FIG. 28). The first and second complementary folding lines 15 a, 15 b; 15 c, 15 d are bounded by a complete transversal cut-off line 16 in the boundary between the single-layered region 2 and the two-layered region 2 a.

The fold can alternatively provide a region with a thickness of more than two layers, or the region of two or more layers can be formed by overlaid, bonded layers of corrugated cardboard or a similar material without the presence of a fold, the technique described in connection with FIGS. 28 and 29 being applicable in any case. When there is a two-layered region 2, said distance d2 is approximately the same as the first distance d1 minus two times the thickness of the corrugated cardboard or a similar material. In general, when the panel has a multilayered region 2 a, the second distance d2 is approximately equal to the first distance d1 minus two times the thickness of the additional layer or layers of said multilayered region 2 a. The first distance d1 is selected so as to provide a spine of a desired width, for instance for housing the members 3, 4, 5, 6 forming the shelves in the compact folded position.

The transversal folding line 15 including the first and second complementary folding lines 15 a, 15 b; 15 c, 15 d and the complete transversal cut-off line 16 are compatible with other longitudinal folding lines 24, including split lines, partial cut-off lines or combinations of both, such as, for instance, the folding lines connecting the rear panel 1 with the side panels 2.

FIGS. 30 and 31 show a fold-out shelving unit according to an additional embodiment of the present invention, which is essentially analogous to the shelving unit previously described in connection with FIG. 13, with the addition of a stepped structure 17 arranged on the shelf panel 4 associated to the support panel 3 forming the base.

FIG. 32 shows the construction of the stepped structure 17, which comprises a top stepped shelf panel 18 having a rear edge hingedly attached to the rear panel 1 and a stepped support panel 19 having a top edge hingedly attached to a front edge of said stepped shelf panel 18 and a bottom edge hingedly attached to the shelf panel 4. In addition, the stepped structure 17 comprises an additional stepped shelf 18 a having a rear edge hingedly attached to the stepped support panel 19 and an additional stepped support panel 19 a having a top edge hingedly attached to a front edge of said additional stepped shelf panel 18 a and a bottom edge hingedly attached to the shelf panel 4.

A skilful artisan will understand that additional further steps can be added, each of them with one corresponding additional stepped shelf panel 18 a with a rear edge hingedly attached to the additional adjacent stepped support panel 19 a and an additional stepped support 19 a with a top edge hingedly attached to the front edge of the additional stepped shelf and a bottom edge hingedly attached to the shelf panel 4. With this construction, irrespective of the number of steps, the stepped structure 17 can be moved from a folded position to an expanded position along with the rear, side, support and shelf panels 1, 2, 3, 4 of the fold-out shelving unit when they are moved between the folded position and the expanded position.

In the embodiment of FIG. 32, which comprises two steps, the stepped shelf panel 18 and a front panel 19 b corresponding to the top step, as well as the additional stepped shelf panel 18 a and the additional stepped support panel 19 a corresponding to the bottom step are formed from a board of corrugated cardboard or a similar material provided with folding lines between the panels and with fastening fins 25, 26 on their ends for the bonded fastening to the rear panel 1 and to the shelf panel 4, whereas the stepped support panel 19 corresponding to the top step is formed by another board of the same material fastened to the inner side of said front panel 19 b and provided on its bottom end with a fastening fin 27 for the bonded fastening to the shelf panel 4. The additional stepped support panel 19 a acts at the same time as a front panel for the bottom step. Other configurations will occur to a skilful artisan without departing from the scope of the present invention.

FIGS. 33 to 35 show a fold-out shelving unit according to another additional embodiment of the present invention, which is entirely analogous to the shelving unit previously described in connection with FIGS. 1 to 5, with the difference that, here, the side panels 2 include top and front reinforcement fins 28, 29 that extend from their top and front edges, respectively (FIG. 33). These top and front reinforcement fins 28, 29 are connected to the respective side panels 2 by means of folding lines 30 and, in a usage situation (FIGS. 34 and 35), they are bent around said folding lines 30 and attached to bottom surfaces of the side panels 2, for instance through an adhesive. This way, the top and front edges of the side panels 2 are reinforced by the top and front reinforcement fins 28, 29 and, in addition, they have a neat appearance, since the internal structure of the corrugated cardboard remains hidden.

In addition, in the front edges of the top and front reinforcement fins 28, 29, there are formed notches 31 having horizontal bottom edges 31 a (FIG. 35) that are at the level of the bottom surfaces of the shelf panels 4 when the fold-out shelving unit is in the expanded position. This way, in the expanded position (FIGS. 34 and 35), the side edges of the shelf panels 4 are in contact with the inner surfaces of the side panels 2 and the front ends of the shelf panels 4 become inserted in the notches 31 and lean on the horizontal bottom edges 31 a thereof, providing therewith additional support for the shelf panel 4. In FIG. 35 the support panel 3 has been omitted for purposes of clarification of the drawing. In the expanded position, however, the shelf panel 4 also leans on the top edges of the support panel 3, of the connection panels 6 and of fastening fins 6 a.

FIG. 36 shows an exploded view of members 3, 4, 5, 6 forming the shelf and its support and cinematic linkage mechanism according to a variation of the same elements described above in connection with FIG. 2. In the variation of this FIG. 36, said members are grouped in only three pieces 33, 34, 35. A first one 33 of the pieces is formed by the shelf panel 4 and its corresponding fastening fin 4 a. The second piece 34 includes the support panel 3, the connection panels 6 and the fastening fins 6 a. The third piece 35 integrates the cinematic linking panel 5, the fastening fin 5 a, which is attached to a front edge of the cinematic linking panel 5 by a folding line and, in a usage situation, is attached to the support panel 3, for instance through an adhesive, and a reinforcement panel 32, which is attached to a rear edge of the cinematic linking panel 5 by a folding line 32 a and, in a usage situation, is attached to the bottom surface of the shelf panel 4, for instance, through an adhesive.

Said reinforcement panel 32 has the same dimensions as the shelf panel 4, which greatly facilitates the positioning of the third piece 35 in the bonding operations. Once bonded, the reinforcement panel 32 provides a global reinforcement of the shelf panel 4 and, in addition, acts as the fastening fin 5 b described above in connection with FIG. 2.

FIGS. 37 to 41 show another additional embodiment of the fold-out shelving unit of the present invention that, like the above embodiments, comprises a rear panel 1, a couple of side panels 2 hingedly attached to opposite vertical edges of the rear panel 1, a shelf panel 4 attached to the rear panel 1 by a horizontal hinge line, a support panel 3 hingedly attached to the side panels 2 by a couple of connection panels 6 forming the first cinematic linking means, and a cinematic linking panel 5 forming the second cinematic linking means hingedly attached, on one end, to the support panel 3 and, on the other end, to the shelf panel 4.

The peculiarity of the embodiment shown in FIGS. 37 to 41 is that the shelf panel 4 and the cinematic linking panel 5 are formed by one single cardboard piece 37 provided with a V-cut 36 (best shown in FIG. 38) which does not affect the underside of the single cardboard piece 37, so that said V-cut 36 forms a transverse hinge. In the expanded position (FIGS. 37, 39 and 40), the shelf panel 4 and the cinematic linking panel 5 are arranged coplanarily in a horizontal position, jointly offering a complete shelf, wherein the facing edges of the V-cut 36 lean on one another providing enough resistance to the shelf to withstand loads not surpassing a predetermined threshold. When the fold-out shelving unit is moved from the expanded position to the folded position, the single cardboard piece 37 bends around the V-cut 36 and the cinematic linking panel 5 fulfils its function as the second cinematic linking means for folding the shelf panel 4.

FIGS. 42 to 44 show yet another additional embodiment of the present invention where the fold-out shelving unit comprises a rear panel 1, side panels 2, a support panel 3, a shelf panel 4, a cinematic linking panel 5, a couple of connection panels 5 and a stepped structure 17 analogous to those described above in connection with FIG. 30. The rear panel 1 and the side panels include a transversal folding line 15. The difference is that, here, the side panels 2 include folding lines 38 parallel to the vertical front edges thereof. The portion of the side panels 2 comprised between these folding lines 38 and said vertical front edges defines fins 39 that, in the expanded position, are arranged coplanarily with the rest of the respective side panels 2 because they are pressed against the connection panels 6 by the force of the elastic member 14.

Nevertheless, when the fold-out shelving unit is moved from the folded position to the compact folded position by bending the rear panel and the side panels 2 along said transversal folding line 15, said fins 39 can be bent inwards along the folding lines 38 and partially overlapped on the stepped structure 17, which is also being folded (FIG. 43). When the fold-out shelving unit is in the compact folded position (FIG. 44), the bent top portion of the rear panel 1 is partially overlapping the fins 39 so that it keeps them from opening, and the fins 39, which, in turn, are partially overlapping the shelf panel 4 and the stepped structure 17, keep the support panel 3, the shelf panel 4 and the stepped structure 17 from expanding as a result of the tension of the elastic member 14.

However, manually starting the lifting of the rear panel 1 suffices for the fins 39 to be freed and for the tension of the elastic member 14 to unleash the expansion of the support panel 3, the shelf panel 4 and the stepped structure 17. As will be understood, the behaviour of the fins 39 would be analogous even if the shelf panel 4 was not associated to the stepped structure 17.

FIGS. 45 and 46 show yet another additional embodiment of the fold-out shelving unit of the present invention similar to that described above in relation to FIGS. 37-41, wherein the main difference is that here two elastic members 14 are provided, each having one end connected to the rear panel 1 and another opposite end connected to a corresponding one of the side panels 2. Preferably, the elastic members 14 are passed through respective openings 40 conveniently formed in the connecting panels 6.

The front edges of the side panels 2 are hingedly connected to front reinforcement fins 41 which in use are folded inwards and adhered to the inner surface of the side panels 2. Cuts in these front reinforcement fins 41 define front hooking members 42 connected to the front reinforcement fins 41 by vertical folding lines. Said front hooking members 42 are not adhered to the inner surface of the side panels 2 so that they can pivot about said folding lines.

The single cardboard piece 37 forming the shelf panel 4 and the linking panel 5 includes a rear fastening fin 4 a hingedly connected to the rear edge of the shelf panel 4 and a front fastening fin 5 a hingedly connected to the front edge of the linking panel 5. In use, said rear and front fastening fins 4 a, 5 a are adhered to the inner surface of the rear panel 1 and to the outer surface of the support panel 3, respectively. Cuts in the rear fastening fin 4 a define rear hooking members 43 connected to the rear fastening fin 4 a by folding lines. Said rear hooking members 43 are not adhered to the inner surface of the rear panel 1 so that they can pivot about said folding lines.

The adhesion of the rear fastening fin 4 a to the rear panel 1 can optionally be reinforced by means of conventional plastic rivets or the like (not shown) installed in corresponding holes previously die-cut in the rear panel 1 and in the rear fastening fin 4 a. These die-cut holes additionally help to the relative positioning of the rear panel 1 and the rear fastening fin 4 a during the adhering operation when the fold-out shelving unit is initially assembled.

The elastic members 14 are for example annular rubber bands hooked to said front and rear hooking members 43, 43 in order to push the rear, side, support, shelf and linking panels 1, 2, 3, 4, 5 towards the expanded position and to keep them therein. Thus, the risk of the fastening fins 6 a, which connect the connecting panels 6 to the side panels 2 in the embodiment of FIGS. 37-41, being pulled out or detached from the side panels 2 due to the tension exerted by the elastic members 14 is avoided. In FIG. 45, the front end of one of the elastic members 14 is shown released from the corresponding front hooking member 42 for illustrative purposes.

Another difference of the embodiment of FIGS. 45 and 46 with respect to that of FIGS. 37-41 is that the mentioned fastening fins 6 a which connect the connecting panels 6 to the side panels 2 are here bent outwards and adhered to the inner surfaces of the side panels 2. This makes the adhering operation easier when initially assembling the fold-out shelving unit because the fastening fins 6 a are not overlapped by the connecting panels 6 when the is in the folded flat position.

Preferably, as better shown in FIG. 46, the support panel 3 is to some extent shorter than the width of the front fastening fin 5 a and the linking panel 5 with the result that gaps are provided between the connecting panels 6 and the side panel 2 when the fold-out shelving unit is in the expanded position. These gaps serve to accommodate the front hooking members 42 therein. In addition, the connecting panels 6, the fastening fins 6 a and the front hooking members 42 are dimensioned so that upper edges thereof provide a support for the linking panel 5 in the expanded position.

A foldable support element 44 having the shape of a rhomboidal ring comprising hinged side walls 47 and rear and front flattened ends 45, 46 is arranged between the rear panel 1 and the support panel 3 below the shelf panel 4 and the linking panel 5. Said rear flattened end 45 of the foldable support element 44 is adhered to the rear fastening fin 4 a which in turn is adhered to the rear panel 1, while the front flattened end 45 of the foldable support element 44 is adhered to the support panel 3, so that the foldable support element 44 is moved between folded and expanded positions together with the rear, side and support panels 1, 2, 3 of the fold-out shelving unit. The foldable support element 44 is dimensioned such that the shelf panel 4 and the linking panel 5 are additionally supported on upper edges of the side walls 47 thereof when the fold-out shelving unit is in the expanded position.

It is to be understood that the general construction of the embodiment shown in FIGS. 45 and 46 can also be used with a shelf panel 4 and a linking panel 5 made as separate parts analogous to those described above in relation to FIGS. 1-4 instead of the shelf panel 4 and the linking panel 5 formed from a single cardboard piece 37 analogous to that described above in relation to FIGS. 37-41.

From the shown and described exemplary embodiments, modifications and variations will occur to a skilful artisan without departing from the scope of the present invention as defined in the attached claims. 

1. A fold-out shelving unit made of cardboard or a similar material comprising: a rear panel (1); side panels (2) hingedly attached to opposite side edges of said rear panel (1) so that they can be moved between a folded position, wherein said side panels (2) and the rear panel (1) are substantially parallel or coplanar, and an expanded position, wherein the side panels (2) are substantially perpendicular to the rear panel (1); at least one support panel (3) extending from one to the other of the side panels (2) in a position substantially parallel to the rear panel (1), and separate therefrom, in said expanded position; and at least one shelf panel (4) movably attached to the rear panel (1) and/or to the side panels so that it can be moved between a folded position, wherein said shelf panel (4) is substantially parallel to the rear panel (1) and to the side panels (2) when the latter are in the folded position, and an expanded position, wherein the shelf panel (4) forms trihedral angles with the rear panel (1) and with the side panels (2) when the latter are in the expanded position, and is supported by said support panel (3); characterised in that the support panel (3) is cinematically linked to the side panels (2) by first cinematic linking means so that the support panel (3) gets closer and away parallel to the rear panel (1) when the side panels (2) move between the folded position and the expanded position, and the shelf panel (4) is cinematically linked to the support panel (3) by second cinematic linking means so that the shelf panel (4) pivots relative to the rear panel (1) when the support panel (3) moves between the folded position and the expanded position.
 2. The fold-out shelving unit according to claim 1, wherein said second cinematic linking means comprise at least one cinematic linking panel (5) having a first edge hingedly attached to the support panel (3) and an opposite second edge hingedly attached to the shelf panel (4) in a position between the support panel (3) and the rear panel (1) when they are in the expanded position.
 3. The fold-out shelving unit according to claim 2, wherein said first cinematic linking means comprise connection panels (6) having a first edge hingedly attached to each side end of the support panel (3) and a second edge hingedly attached to each side panel (2) in a position between the support panel (3) and the rear panel (1) when they are in the expanded position.
 4. The fold-out shelving unit according to claim 2, wherein said first cinematic linking means comprise, in each side panel (2), a longitudinal folding line (7) substantially parallel to the corresponding side edge of the rear panel (1) and located between the support panel (3) and the rear panel (1) when they are in the expanded position, wherein side edges of the support panel (3) are hingedly attached to the side panels (2) on or near their free edges.
 5. The fold-out shelving unit according to claim 1, wherein the shelf panel (4) has a longitude from its rear edge to its front edge selected so that a front region thereof is supported by a top edge of the support panel (3) when they are in the expanded position.
 6. The fold-out shelving unit according to claim 1, wherein the shelf panel (4) has a longitude from its rear edge to its front edge selected so that a front region thereof is supported by a projection (8) protruding from the inner side of the support panel (3) when they are in the expanded position.
 7. The fold-out shelving unit according to claim 2, wherein said cinematic linking panel (5) forms an acute angle with the shelf panel (4) when they are in the expanded position so as to provide additional support to the shelf panel (4).
 8. The fold-out shelving unit according to claim 3, wherein said connection panels (6) are supported by respective projections (9) protruding from an inner side of the corresponding side panels (2) when they are in the expanded position.
 9. The fold-out shelving unit according to claim 1, wherein a foldable support structure (10) is arranged between the shelf panel (4) and a support surface on which the shelving unit rests in the expanded position, said support structure (10) comprising at least two vertical structure panels (11, 12, 13 a-13 e) hingedly attached to one another and each being hingedly attached to at least one of the rear, side and support panels (1, 2, 3) so that the support structure (10) is moved between a folded position and an expanded position along with the rear, side and support panels (1, 2, 3) when the latter are moved between the folded position and the expanded position.
 10. The fold-out shelving unit according to claim 9, wherein said structure panels (11, 12, 13 a-13 e) have top edges arranged to support the shelf panel (4) and bottom edges arranged to rest on said support surface when they are in the expanded position.
 11. The fold-out shelving unit according to claim 1, wherein retention means are arranged to keep the rear, side and support panels (1, 2, 3) in the expanded position.
 12. The fold-out shelving unit according to claim 11, wherein said retention means comprise at least one elastic member (14) arranged to push the rear, side and support panels (1, 2, 3) towards the expanded position and keep them therein.
 13. The fold-out shelving unit according to claim 12, wherein said elastic member (14) is arranged to pull the side panels (2) towards one another.
 14. The fold-out shelving unit according to claim 13, wherein the elastic member (14) is arranged adjacent to an underside of the shelf panel (4) when it is in the expanded position.
 15. The fold-out shelving unit according to claim 12, wherein the elastic member (14) is an annular rubber band.
 16. The fold-out shelving unit according to claim 1, wherein the rear panel (1) and the side panels (2) comprise at least one transversal folding line (15) substantially perpendicular to the side edges of the rear panel (1) so that the shelving unit can be moved from the folded position to a compact folded position by bending the rear panel (1) and the side panels (2) along said transversal folding line (15).
 17. The fold-out shelving unit according to claim 16, wherein the transversal folding line (15) comprises two mutually parallel first complementary folding lines (15 a, 15 b) separated by a first distance (d1) selected so as to provide a spine of a desired width, wherein each first complementary folding line (15 a, 15 b) comprises, in at least one section of its length, a partial cut-off line on an outer side of the panel and a folding line on the opposite, inner side of the panel.
 18. The fold-out shelving unit according to claim 17, wherein at least one of the rear and side (2) panels has a multilayered region (2 a), and the transversal folding line (15) comprises, in that multilayered region (2 a), two mutually parallel second complementary folding lines (15 c, 15 d) separated by a second distance (d2) smaller than said first distance (d1), wherein each second complementary folding line (15 c, 15 d) comprises a partial cut-off line on an outer side of the multilayered region (2 a) of the panel and a folding line on the opposite, inner side of the multilayered region (2 a) of the panel.
 19. The fold-out shelving unit according to claim 18, wherein said first and second complementary folding lines (15 a, 15 b; 15 c, 15 d) are bounded by a complete transversal cut-off line (16).
 20. The fold-out shelving unit according to claim 18, wherein said second distance (d2) is approximately equal to the first distance (d1) minus two times the thickness of the additional layer or layers of said multilayered region (2 a).
 21. The fold-out shelving unit according to claim 1, wherein, on the shelf panel (4), there is a stepped structure (17) comprising at least one stepped shelf panel (18) with a rear edge hingedly attached to the rear panel (1), and a stepped support panel (19) with a top edge hingedly attached to said stepped shelf panel (18) and a bottom edge hingedly attached to the shelf panel (4), so that said stepped structure (17) can be moved between a folded position and an expanded position along with the rear, side, support and shelf panels (1, 2, 3, 4) when the latter are moved between the folded position and the expanded position.
 22. The fold-out shelving unit according to claim 21, further comprising at least one additional stepped shelf panel (18 a) with a rear edge hingedly attached to the stepped support panel (19) or to another additional adjacent stepped support panel (19 a) and an additional stepped support panel (19 a) with a top edge hingedly attached to said additional stepped shelf panel (18 a) and a bottom edge hingedly attached to the shelf panel (4).
 23. The fold-out shelving unit according to claim 2, wherein the shelf panel (4) and the cinematic linking panel (5) are formed as a single cardboard piece (37) provided with a transverse hinge, so that the shelf panel (4) and the cinematic linking panel (5) are arranged coplanarily, jointly forming a complete shelf in the expanded position.
 24. The fold-out shelving unit according to claim 21, wherein the side panels (2) include folding lines (38) parallel to the front vertical edges thereof, wherein a portion of the side panels (2) comprised between these folding lines (38) and said front vertical edges defines fins (39) that, in an expanded position, are arranged coplanarily with the rest of the respective side panels (2) and, in the compact folded position, are arranged partially overlapping the shelf panel (4) and the stepped structure (17), while a portion of the rear panel (1) is arranged partially overlapping the fins (39).
 25. The fold-out shelving unit according to claim 1, wherein the shelf panel (4) has a rear edge hingedly attached to the rear panel (1).
 26. The fold-out shelving unit according to claim 3, wherein retention means are arranged to keep the rear, side and support panels (1, 2, 3) in the expanded position, said retention means comprising two elastic members (14) each having one end connected to the rear panel (1) and another opposite end connected to a corresponding one of the side panels (2), with said elastic members (14) being passed through respective openings (40) formed in said connecting panels (6).
 27. The fold-out shelving unit according to claim 3, wherein front edges of the side panels (2) are hingedly connected to front reinforcement fins (41) which are folded inwards and adhered to an inner surface of the side panels (2), and front hooking members (42) non adhered to said inner surface of the side panels (2) are connected to said front reinforcement fins (41) by folding lines, wherein a single cardboard piece (37) forming the shelf panel (4) and a linking panel (5) connected to shelf panel (4) by a transverse hinge includes a rear fastening fin (4 a) hingedly connected to a rear edge of the shelf panel (4) and a front fastening fin (5 a) hingedly connected to a front edge of said linking panel (5), said rear and front fastening fins (4 a, 5 a) being adhered to the inner surface of the rear panel (1) and to the outer surface of the support panel (3), respectively, and rear hooking members (43) non adhered to the inner surface of the rear panel (1) are connected to the rear fastening fin (4 a) by folding lines, and wherein each of said elastic members (14) is hooked to said front and rear hooking members (42, 43).
 28. The fold-out shelving unit according to claim 3, wherein a foldable support element (44) is arranged between the rear panel (1) and the support panel (3) below the shelf panel (4) and the linking panel (5), said foldable support element (44) having the shape of a rhomboidal ring with hinged side walls (47) and rear and front flattened ends (45, 46), with said rear flattened end (45) being adhered to the rear fastening fin (4 a) which in turn is adhered to the rear panel (1), and with the front flattened end (45) adhered to the support panel (3), so that the foldable support element 44 is moved between folded and expanded positions together with the rear, side and support panels (1, 2, 3), the shelf panel (4) and the linking panel (5) being supported on upper edges of said side walls (47) of the foldable support element (44) when the fold-out shelving unit is in the expanded position.
 29. The fold-out shelving unit according to claim 23, wherein said transverse hinge is provided by a V-cut (36) affecting only the top side of said single cardboard piece (37), said V-cut (36) having facing edges which lean on one another in the expanded position. 